The effect of aluminum particles dispersity on characteristics of ammonium perchlorate—aluminum composition laser ignition

Prop., Explos., Pyrotech.

Reshetov

et al. 2017

The experimental investigations of laser‐induced ignition and heat action of ammonium perchlorate and aluminum powder mixtures are presented in this paper. A laser pulse with wavelength of 1.06 μm and duration of 3.5 ms was used. Powder mixtures of different dispersion were tested, namely, coarsely dispersed powders and nanopowders with average surface diameters of 80 and 0.25 μm, respectively. The values of ignition thresholds and delays of the mixtures activity in air were measured, and experimental results for different exposure conditions were obtained. The possible reasons of different sensitivity for the given mixtures to laser pulse and heat action are discussed.

Section: Introductionmentioning

confidence: 83%

Conditions of Millisecond Laser Ignition and Thermostability for Ammonium Perchlorate/Aluminum Mixtures

Prop., Explos., Pyrotech.

Reshetov

et al. 2017

“…It is necessary to consider that the laser pulse exposure leads to the near‐surface layer thermal hotspot formation. The hotspot is limited by the size of the laser beam ( d s =2 mm), by the light propagation depth h ( h=

\frac{1}{μ}

= 2.5 μ

normalm

; μ =3700 cm −1 ) and by the thickness of the heated layer

\sqrt{α τ} = 10 μ m

.…”

Section: Resultsmentioning

confidence: 99%

“…The ignition thresholds were determined according to the methods reported in . Firstly, the dependence P(E) within the range of 0–1 was obtained, where P is the ratio of the number of ignitions to the number of experiments, and E is the energy density of laser radiation.…”

Section: Methodsmentioning

confidence: 99%

“…The ignition thresholds were determined according to the methods reported in [8,16]. Firstly, the dependence P(E) within the range of 0-1 was obtained, where P is the ratio of the number of ignitions to the number of experiments, 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 and E is the energy density of laser radiation.…”

Section: Methodsmentioning

confidence: 99%

“…Pulsed laser radiation can induce local overheat of the sample surface and subsequent gas relief [8]. The latter can be critical for self-sustaining reaction propagation in many energetic materials [9,10].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Effect of Ammonium Perchlorate and Aluminum Composition Density on Characteristics of Laser Ignition

Propellants Explo Pyrotec

Forat

2018

Laser ignition of stoichiometric mixture based on aluminum nanopowder and ammonium perchlorate were studied experimentally. The laser with a radiation wavelength of 1.06 μm and a pulse duration of 0.8 ms was used as a source of heat. The ignition thresholds were determined for open samples in the air and for samples confined with transparent dielectric. The difference in the obtained data is discussed within the thermal ignition theory.

Laser Ignition of Ammonium Perchlorate/Aluminum Composition Confined into PMMA Capsule

Forat

Propellants Explo Pyrotec

et al. 2022

A two-component composition of ammonium perchlorate and nanosized aluminum powder can be ignited by millisecond Nd laser radiation. However, the mixture exposed to laser radiation pulse through polymethyl methacrylate (PMMA) capsule demonstrates less sensitivity when compared to ignition of the uncovered sample. Such behavior is uncommon to gasified energetic materials. It is shown that the sensitivity of uncovered samples does not change if the surrounding atmosphere is changed from air to argon. It was found that the cover of PMMA decreases the sensitivity of the mixture due to heat dissipation from the ignition zone, thereby reducing its reactivity.